Substituted quinazolines (I), ##STR1## such as those described in EP 326,329, are valuable as plant fungicides, miticides and insecticides. Compounds of this family have generally been prepared by the reaction between a 4-haloquinazoline and an alcohol. The 4-haloquinazolines in turn are prepared by the halogenation of the corresponding 4-hydroxyquinazolines.
The recommended procedure for converting a 4-hydroxyquinazoline to the corresponding 4-halo-quinazoline calls for the use of a relatively unstable triphenylphosphite-halogen complex as the preferred halogenating agent. This procedure requires at least one equivalent of triphenylphosphite-halogen reagent, the use of an additional equivalent of a tertiary amine base, an inert organic solvent and operation at less than about -15.degree. C. In addition, the process is relatively complex, involving numerous recovery and recycle operations. A simplified process that eliminates some of the drawbacks associated with the use of triphenylphosphite-halogen as the halogenating agent is highly desirable.